Abstract :
[en] Accumulation of trace metals and metalloids (TMM) in organisms leads to oxidative stress, causing severe structural damages. In the last decades, TMM have been suggested as a threat for bee populations, due to their increasing concentrations in the environment. In a review, we aimed at bringing together all the studies (n = 60) that assessed the effects of TMM on bee health. Most studies focussed on cadmium, copper and lead (~ 80%), leaving knowledge gaps around other important pollutants. In addition, the majority of studies assessing sublethal effects of TMM focussed on honey bee workers (~ 75%), leaving out other castes, life stages and bee species (> 99% of bee species). Lethal effects are also reported in the literature, but LD50 are scarcely assessed. In addition, studies that examined the impacts of TMM on reproduction (i.e., fitness) are rare. We plan to partly address the dearth of knowledge around the effects of TMM on bees. For this purpose, using copper and cadmium as TMM and the commercial bumble bee Bombus terrestris as bee model, we have designed experiments (i) to determine LD50 both for larvae and adults, and both for worker and male castes; (ii) to assess whether bumble bees can detect TMM in their nutritional resources; (iii) to examine sublethal impacts of TMM at behavioural, physiological and histological levels; and (iv) to assess the impacts of sublethal doses of TMM on queen reproduction, hibernation and colony initiation success. Recently, we have computed the LD50 of copper and cadmium on worker and male adults, and compared these values with concentrations found in bees’ substrates in the wild. Besides, we have run experiments to assess whether field-realistic concentrations of these TMM have sublethal impacts on worker flying and walking behaviours.
